In any growing community, the need for fresh water keeps pace with the population. Where fresh water is derived from rivers and freshwater lakes, it is common for the system effluent (wastewater) to be treated and then returned to the original source. In order to avoid harming the environment, local legislation usually establishes minimal limits for the quality of the wastewater that is discharged into the environment.
One such characteristic is the pH level (acid-base level). Specifically, it is regarded as desirable that the pH of wastewater being discharged into the environment should not drop below 6 (a pH of 7 being neutral).
To control the pH of the wastewater, particularly involving industrial aqueous effluent, a number of different processes are presently in common use. These processes usually are based on the addition of carefully measured alkaline reagents to the effluent, using a variety of process control mechanisms.
All of these pH control systems rely on the continuous measurement of the pH of the treated water and often also on the pH of the raw effluent. The measurement data thus obtained are then used through a control mechanism to add the required amount of reagent to achieve the desired result.
This prior approach is subject to a number of problems that can cause variations in the effluent pH, and tend to be labour and maintenance intensive. For example, the neutralizing agents commonly utilized are difficult to handle, hazardous, and often require special training for their proper use.
Despite recent developments in this area, there remains a need for a contact system for the neutralization of acidic waters, which is automatic, efficacious, and cost-effective.